Field of the Invention
The subject device and associated system relates generally to assessing impairment of an individual to determine whether to provide access to operate a motor vehicle, providing an ignition interlock that works without requiring modification in a motor vehicle and allowing an individual to start the motor vehicle only following measurement of blood alcohol content or following a series of cognitive tasks to determine the level of impairment.
Description of the Related Art
Driver fitness is typically considered a function of sensory, motor, and cognitive skills. The most common cause of impairments is the influence of alcohol. In most countries, the allowable level of blood alcohol is determined by law. In some countries it is zero; in the United States it is 0.08%, although lower level intoxication can result in result in a criminal offense in a number of states, and many states have lower level limits for younger operators. It is well documented that younger people, especially teen drivers, are prone to more risky behavior even at very low levels of blood alcohol levels. This phenomenon couples with a reduced performance in cognitive abilities caused by intoxication. Over the past decade, the number of fatal accidents recorded every year has not changed significantly any more, despite the introduction of new safety features in cars. Statistics show that drivers who are caught or get involved in an accident with elevated alcohol levels are likely to have driven many times in intoxicated condition before. Hence the biggest opportunity for further reducing the number of accidents is by focusing on technology that prevents impaired driving. With alcohol being the most common cause of impairment, it should be the first problem to be dealt with.
The most accurate measurement method for determining blood alcohol content involves drawing blood. Such an approach would be used only in extreme cases, for example after a serious accident.
The most established non-invasive technology for measuring the blood alcohol content is a breathalyzer. The breathalyzer technology is used by law enforcement authorities. Breathalyzer technology is available for built in applications in automobiles, where a car cannot be started when the breathalyzer detects a level of alcohol higher than the set limit. Built in breathalyzers are primarily used when required by a judge for operators with drunk driving convictions. This ignition interlock technology is expensive and requires customer installation.
The proposed invention makes it possible to incorporate a breathalyzer into a portable device which acts as an ignition interlock using just the car key provided by the automobile manufacturer.
Alternative non-invasive methods for measuring blood alcohol content have been previously proposed. It is possible to use an infrared scanner to analyze for alcohol in the blood through the skin. Numerous research publications support the conclusion that such sensors can correlate quite accurately with blood measurements and breathalyzer data, although there is a larger lag time for alcohol to show up in the perspiration, which is what the infrared sensors measure. There appear to be two key obstacles that have held back the deployment of infrared alcohol sensors for alcohol detection in a broader way with vehicle start interlocks. These are, a) it is difficult to prevent the alcohol sensor from being bypassed, e.g. the system has to make sure it is testing the operator's skin, and b) the systems that are being pursued require a complex installation process in the vehicles. Both of these challenges limit adoption of the alcohol sensor technology in commercial use in vehicles. In one embodiment of the proposed invention, the device and system provide an ignition interlock that does not require installation in an automobile, and the combination of a biometric fingerprint sensor and infrared alcohol sensor limit the possibility of manipulating the system.
Another approach for determining impairment is to use cognitive tests which can be made available on mobile devices. Cognitive tests have the advantage that they can reveal impairments due to causes other than alcohol consumption, such as exhaustion, drugs, or certain medical conditions. For this reason, it is desirable to make it possible to use methods and systems implementing cognitive tests on mobile devices such as smartphones, watches and tablet computers in conjunction with vehicle start interlocks, or at least with notifications of interested parties such as guardians or employers.